In the formation of dental restorations, the dentist, prepares the tooth by removing diseased portions, and any other portions needed to mount a replacement surface on the treated tooth. In the case of teeth subjected to root canal treatment, the nerves are removed from the tooth portions deep below the gum line. In other, e.g. crown work, a gold or like material cover is used and is fitted onto the tooth with great precision for reasons of comfort, appearance and disease control. For example, the dentist cuts a "margin" to which the crown is seated exactly. The dental technician receives from the dentist a negative or "impression" of the tooth surface to be restored, and of the adjoining teeth as well. In the dental lab a positive of the tooth area, is prepared using the negative impression as a mold to make a "model". Certain of the teeth for which crowns are to be made for example are required as well. Others have proposed use of two dowel pins on a common base, which blocks rotation but is deficient in cocking resistance in other than the transverse direction. Also the great size of such pin arrangements prohibits their use where very small teeth are involved.